Aspects of the present disclosure relate generally to fiber optic cables.
Stretching or straining of optical fibers may increase attenuation of signals communicated via the optical fibers. Accordingly, fiber optic cables may be designed with strength components to minimize stretching of the cable and correspondingly minimize stretching of the optical fibers.
In some fiber optic cable designs, the optical fibers may be loosely arranged in tubes in the fiber optic cables called buffer tubes. The buffer tubes generally have free space that allows the optical fibers to have excess optical fiber length relative to the length of the respective buffer tubes. As the buffer tubes stretch, the optical fibers straighten within the buffer tubes, but are not strained until all of the excess optical fiber length in the optical fibers is removed, providing a “strain window.”
Applicants have found that excess optical fiber length may vary at least in part due to the process of manufacturing the buffer tubes. The variation may be with respect to individual optical fibers within a buffer tube as well as between optical fibers of different buffer tubes in the same cable. Further, Applicants have found that the degree of excess optical fiber length may additionally be modified by time, temperature, and subsequent processing of the buffer tubes during the manufacturing of the corresponding fiber optic cable, both in winding the buffer tubes around a central strength member, called “stranding,” and when applying a protective jacket around the stranded buffer tubes, called “jacketing.”
Strength components of fiber optic cables are typically selected to accommodate the lower end of the range of excess optical fiber lengths. Put another way, the strength components are be sized and configured to prevent straining and attenuation of the optical fibers of the cable that have the least amount of excess optical fiber length. Such magnitude of strength may be unnecessary for optical fibers of the cable having a greater amount of excess optical fiber length.